KR101975940B1 - Nanostructure fabrication method and method of making the stamp used for nanostructure fabrication - Google Patents

Abstract

The present invention relates to a method of manufacturing a nanostructure and a method of manufacturing a stamp for manufacturing a nanostructure, and more particularly, to a nanostructure manufacturing method capable of forming a finer channel by combining a metal catalyst etching method and a nanoimprint lithography technique, To a stamp manufacturing method. The present invention provides a method of manufacturing a semiconductor device, comprising: forming a sandwich with the metal catalyst thin film sandwiched between the base and the substrate by bringing a stamp including a base part having at least one metal catalyst thin film on one surface thereof into contact with the substrate; And forming a nanochannel on the substrate by an etching phenomenon caused at an edge of the metal catalyst thin film.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a nanostructure fabricating method and a nanostructure fabricating method,

The present invention relates to a nanostructure manufacturing method and a method for manufacturing a stamp for manufacturing a nanostructure, and more particularly, to a nanostructure manufacturing method capable of forming a finer channel by combining a metal catalyst etching method and a nanoimprint lithography technique, And a manufacturing method thereof.

The present invention relates to a nano imprint lithography technique that combines a metal catalyst etching method and a nano imprint lithography technique so as to manufacture a channel of several tens of nanometers or less.

The nanoimprint lithography technology is a technology for repetitively transferring a nanostructure by pressing a stamp imprinted with a nanostructure onto a resist surface of a polymer material coated on the substrate.

The nanoimprint process can be relatively simple, and the stamp can be used repeatedly. Therefore, nanoimprint technology is attracting attention as a next generation lithograph technique that can realize fine patterning economically and efficiently.

However, as the pattern of the stamp (concave-convex portion) is miniaturized to a few tens of nanometers (nm) or less, the process of transferring the resist to the resist is not easy, and further limitation of the pattern size is limited.

Focused Ion Beam (FIB) milling techniques and anisotropic etching techniques using KOH-containing etching solutions have been tried as alternatives to nanoimprint lithography. However, since the FIB milling technique is a sequential process, there is a disadvantage that the process cost and time are increased together with the increase in the number of devices integrated on one wafer, and anisotropic etching technology using KOH- There is a problem that the channel can not be produced.

Accordingly, there is a demand for a technique for improving the nanoimprint process and the stamp so as to use the nanoimprint lithography technique even when the nanostructure to be manufactured becomes finer than a few tens of nanometers (nm).

Korean Patent Laid-Open Publication No. 2013-0020425 relates to a technique for manufacturing an end portion of a stamp pattern protrusion in a concave shape to improve the etching process characteristics after imprinting.

However, this method does not directly miniaturize the pattern size.

1. Korean Patent Publication No. 2013-0020425

Accordingly, it is an object of the present invention to provide a nanostructure manufacturing method capable of forming a finer channel by combining a metal catalyst etching method and a nanoimprint lithography technique, and a method of manufacturing a stamp for manufacturing a nanostructure.

Other objects of the present invention will become readily apparent from the following description of the embodiments.

According to another aspect of the present invention, there is provided a method for fabricating a nanostructure, the method including: a step of bringing a stamp for fabricating a nanostructure, which includes a base having at least one metal catalyst thin film on one surface thereof, Forming a sandwich-type bonded body in which the metal catalyst thin film is sandwiched between the substrate and the substrate; And dipping the sandwich-type assembly in a substrate etching solution to form a nanochannel along a boundary line of the edge of the metal catalyst film on the substrate by an etching phenomenon caused at an edge of the metal catalyst thin film .

The base portion includes a protrusion having at least one protrusion, and the metal catalyst thin film is provided at an end of the protrusion, and the plan view of the protrusion may be a pattern of the nanochannel to be formed.

Further, the depth of the concavo-convex portion may be 15 mu m to 30 mu m.

In addition, an adhesive layer may be provided between the metal catalyst thin film and the base portion.

Further, the adhesive layer may be selected from titanium, chromium, nickel, and mixtures thereof.

The adhesive layer may have a thickness of 3 nm to 7 nm.

The method may further include separating the stamp from the sandwich and removing the metal catalyst remaining on the substrate.

The metal catalyst thin film may be selected from gold, silver, platinum, iron, nickel, cobalt, copper, lead, aluminum, palladium and mixtures thereof.

The metal catalyst thin film may have a thickness of 20 nm to 50 nm.

The substrate may be a single crystal semiconductor substrate, a III-V compound semiconductor substrate, a silicon on insulator (SOI) substrate, a germanium substrate, or a silicon-germanium substrate.

The base may be a single crystal semiconductor substrate, a III-V compound semiconductor substrate, a polymer substrate, a glass substrate, or a metal substrate.

The etching solution for the substrate includes fluoric acid, sulfuric acid, hydrogen peroxide, silver nitrate, potassium chloroauric acid, chloroauric acid, chloroauric acid, potassium chloroplatinic acid, chloroplatinic acid, ferric nitrate, nickel nitrate, magnesium nitrate, sodium persulfate, potassium permanganate and potassium bichromate Mixed solution.

According to another aspect of the present invention, there is provided a method of fabricating a nanostructure stamp, including: forming a mask pattern on a stamp substrate; Etching the stamp substrate with a stamp substrate etching solution to form a base portion including a recessed portion having at least one protrusion; Removing the mask pattern of the stamp substrate; And forming a metal catalyst thin film on the end of the protrusion.

The method may further include forming an adhesive layer on the stamp substrate between the step of removing the mask pattern of the stamp substrate and the step of forming the metal catalyst thin film on the end of the protrusion.

Further, the adhesive layer may be selected from titanium, chromium, nickel, and mixtures thereof.

The adhesive layer may have a thickness of 3 nm to 7 nm.

Here, the stamp substrate may be any one of a single crystal semiconductor substrate, a III-V compound semiconductor substrate, a polymer substrate, a glass substrate, and a metal substrate.

The stamp substrate etching solution may be a solution of hydrofluoric acid, sulfuric acid, hydrochloric acid, nitric acid, boric acid, phosphoric acid, or a mixed solution thereof.

The concavo-convex portion may have a depth of 15 mu m to 30 mu m.

In addition, the metal catalyst thin film formed may be selected from gold, silver, platinum, iron, nickel, cobalt, copper, lead, aluminum, palladium and mixtures thereof.

The metal catalyst thin film may have a thickness of 20 nm to 50 nm.

As described above, the present invention can provide a nanostructure manufacturing method capable of forming finer channels and a method of manufacturing a stamp for manufacturing a nanostructure, by combining the metal catalyst etching method and the nanoimprint lithography technique.

1A is a diagram showing two modes of operation in which metal catalyst etching phenomenon is diffused.
Fig. 1 (b) is a view showing a method of controlling the operation mode in which the metal catalyst etching phenomenon is diffused by the stamp.
FIG. 2 illustrates a method of fabricating a nanostructure according to an embodiment of the present invention. Referring to FIG.
3 is a view illustrating a method of manufacturing a stamp for manufacturing a nanostructure according to an embodiment of the present invention.
4 is a view illustrating a method of manufacturing a stamp for manufacturing a nanostructure according to another embodiment of the present invention.
5 is a SEM (scanning electron microscopy) photograph of a cross-section of a nanochannel manufactured according to an embodiment of the present invention.
6 is an SEM (scanning electron microscopy) photograph of the surface of a nanostructure fabricated according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for like elements in describing each drawing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, .

On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention.

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, a method for fabricating a nanostructure of the present invention will be described in detail with reference to the accompanying drawings.

The applicant of the present invention conducted a study to fabricate nanostructures of several tens of nanometers (nm) or less using nanoimprint lithography technology. As a result, the contact area between the metal catalyst thin film and the etching solution was controlled by stamping, The present invention has been completed based on this finding.

The principle of metal catalytic etching is described below for a metal catalyst thin film and a silicon substrate.

When the metal catalyst thin film is contained in a solution of an oxidizing agent (H ₂ O ₂ , KMnO _4, etc.), it functions as a catalyst promoting the reduction reaction of the oxidizing agent. The silicon substrate coated with the metal catalyst thin film is etched by a silicon etching When immersed in a solution, the reaction shown in Reaction Scheme 1 below occurs on the surface of the metal catalyst thin film.

[Reaction Scheme 1]

Then, the generated free holes are diffused into the silicon substrate on which the metal catalyst thin film is covered, and then the silicon substrate is oxidized, and the oxidized silicon substrate is etched by the hydrofluoric acid contained in the silicon substrate etching solution. The reaction takes place.

[Reaction Scheme 2]

As a result, the etching rate in the silicon substrate under the metal catalyst becomes faster than the etching rate in the portion of the silicon substrate where the metal is not covered, and the layer covered with the metal catalyst thin film sinks, which is called metal assisted chemical etching. In order for the oxidized silicon substrate region to be continuously etched by the catalytic reaction of the metal catalyst thin film, the silicon atoms to be oxidized must be in constant contact with the silicon etching solution.

FIG. 1 (a) is a view showing two modes of operation in which a metal catalyst etching phenomenon proceeds in a silicon substrate. Referring to FIG. 1 (a), in the state where the metal catalyst thin film covers the silicon substrate, the process of the metal catalyst etch reaction by the silicon atom continuously contacted with the silicon atom to be oxidized may occur in two operation modes. The first mode of operation is a case in which a silicon atom to be oxidized is brought into contact with a silicon etching solution along the interface between metal and silicon as shown by model 1 in FIG. 1 (a) , The silicon atom to be oxidized passes through the metal as it is and comes into contact with the silicon etching solution.

FIG. 1 (b) is a view showing a method of controlling the action of the metal catalyst etching phenomenon with a stamp. Referring to FIG. 1 (b), a pattern 201 is formed on a stamp 201 including a base portion made of a material which does not react with a silicon substrate etching solution, and a pattern is formed on the metal catalyst thin film 220, 1 (a) is blocked by the stamp 201 so that metal catalyst etching does not occur immediately below the layer covered with the metal catalyst thin film 220, and metal Metal catalytic etching may occur only in the vicinity of the edge 300 of the catalyst thin film through the same operation mode as that of the model 1 of FIG. 1 (a). Using this, it is possible to fabricate nanochannels such as the edge 300 pattern of the metal catalyst thin film. The width of the fabricated channel can be much smaller than the metal catalyst thin film pattern.

FIG. 2 illustrates a method of fabricating a nanostructure according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 2, a method of fabricating a nanostructure according to an exemplary embodiment of the present invention includes a step of forming a base (210) having at least one metal catalyst thin film on one surface thereof, as shown in FIG. 2 (a) 201 are brought into close contact with the substrate to form a sandwich-type bonded body in which the metal catalyst thin film 220 is sandwiched between the base portion 210 and the substrate 100. The substrate 100 may be a single crystal semiconductor substrate, a III-V compound semiconductor substrate, a silicon on insulator (SOI) substrate, a germanium substrate, or a silicon-germanium substrate. At this time, the base 210 is made of a material which can not be etched by the following substrate etching solution. More specifically, the base 210 is made of a single crystal semiconductor substrate, a III-V compound semiconductor substrate, a polymer substrate, Can be used. The metal catalyst thin film 220 may be selected from gold, silver, platinum, iron, nickel, cobalt, copper, lead, and mixtures thereof, which may cause metal catalytic etching.

The thickness of the metal catalyst thin film 220 is suitably 20 to 50 nm. If the thin metal film is too thick, the metal catalyst thin film 220 may be separated from the base 210. If the thickness of the thin metal film is thin, It is difficult to clarify.

Next, as shown in FIG. 2 (b), a sandwich-type bonded body in which the metal catalyst thin film 220 is sandwiched between the base portion 210 and the substrate 100 is immersed in a substrate etching solution to form a metal catalyst thin film 220 The nano channel 110 is formed on the substrate by an etch phenomenon induced at the edge of the nanochannel. The substrate etch solution is suitable for etching the substrate 100, and more specifically, it may be formed of a metal such as hydrofluoric acid, sulfuric acid, hydrogen peroxide, silver nitrate, potassium chlorate, chlorine gold, chloroplatinic acid, chloroplatinic acid, , Sodium persulfate, potassium permanganate, and potassium dichromate. The substrate etch solution may be characterized by adjusting the height and orientation of the nanochannel by varying at least one of composition, concentration, etch temperature, and etch time. However, if the substrate is silicon, hydrofluoric acid should be included in the substrate etching solution, and if the substrate is a III-V compound semiconductor substrate, sulfuric acid may be contained in the substrate etching solution. It was experimentally demonstrated that when the substrate is a silicon substrate and hydrofluoric acid, hydrogen peroxide, and water are mixed at a ratio of 40: 3: 60 and the bonded body in the form of a sandwich is etched at room temperature for 1 hour, a nanochannel having a depth of about 250 nm can be formed .

Next, as shown in Fig. 2 (c), the stamp 201 is separated from the sandwich type combined body, and the metal catalyst remaining on the substrate is removed. On the substrate 100 from which the remaining metal catalyst is removed, the nano channel 110 may be formed in the form of the edge of the metal catalyst thin film pattern. When removing the metal catalyst, a corrosive liquid of the metal may be used.

The stamp used in the method for fabricating a nanostructure according to an embodiment of the present invention may be a stamp including a base portion including a concavo-convex portion having at least one protrusion having a metal catalyst thin film at an end thereof. In performing the nanochannel manufacturing method according to an embodiment of the present invention, using such a stamp may have at least two advantages compared to a stamp including a base portion that does not include a concave-convex portion. The first advantage is that when the substrate is immersed in the etching solution, the space between the substrate and the base of the stamp is widened due to the unevenness, so that the supply of the substrate etching solution can be increased. A second advantage is that the process of recovering the metal catalyst thin film pattern can be facilitated if the metal catalyst thin film pattern at the end of the protrusion is damaged after continuously processing a plurality of substrates by the method of manufacturing a nanostructure according to an embodiment of the present invention . In the case of the stamp including the base portion not including the concave / convex portions, since the process of forming the mask pattern, depositing the metal catalyst thin film, and removing the mask are all required to recover the metal catalyst thin film pattern, It is possible to have the same complexity as in the case of forming the metal catalyst thin film pattern on the substrate. However, in the case of a stamp including a base portion including a concavo-convex portion having at least one projecting portion provided with a metal catalyst thin film at an end thereof, if the metal catalyst thin film pattern formed at the end of the projecting portion is damaged by a single process of vapor- can do. In the process of depositing the metal catalyst thin film, a metal complex or an alkoxide of a metal may be dissolved in a solvent such as alcohol and then coated on a stamp to be dried, or a metal deposition method such as thermal deposition or sputtering may be used.

When the depth of the recesses and protrusions is shallow, the depressed portion of the recesses and protrusions forming the metal catalyst thin film is exposed to the outside of the metal catalyst Is buried in the process of depositing the thin film, and thus the metal catalyst thin film pattern at the end may become unclear. Therefore, it is preferable that the depth of the concave-convex portion is larger than the thickness of the metal catalyst thin film, specifically, it may be 15 占 퐉 to 30 占 퐉 or more.

3 is a view illustrating a method of manufacturing a stamp for manufacturing a nanostructure according to an embodiment of the present invention.

Referring to FIG. 3, a stamp manufacturing method according to an embodiment of the present invention forms a mask pattern 230 on a stamp substrate 200 as shown in FIG. 3 (a). The stamp substrate 200 is preferably etched in the etching solution for the substrate, but is preferably made of a material that can not be etched in the etching solution for the substrate. Specifically, when the substrate is made of silicon, the stamp substrate is made of an indium phosphide substrate or a polymer substrate . Various process techniques can be used for mask pattern formation, specifically, optical lithography and nanoimprint lithography processes can be used, and materials used for mask patterns can be photoresist.

Next, as shown in FIG. 3 (b), the stamp substrate is etched with a stamp substrate etching solution to form a recess 211 having at least one protrusion 212 and a base 210 including the protrusion 211. The stamp substrate etching solution is suitable for etching the stamp substrate 200. More specifically, when the stamp substrate is indium phosphide, a mixed solution containing boric acid, phosphoric acid, and hydrochloric acid can be selected. The depth of the concave and convex portions 211 may be controlled by changing at least one of the composition, the concentration, the etching temperature, and the etching time of the stamp substrate etching solution. The depth of the concave and convex portions 211 is preferably larger than the thickness of the metal catalyst thin film to be formed, and may be 15 占 퐉 to 30 占 퐉 or more. When the stamp substrate 200 is an indium phosphide substrate and etching is performed at room temperature for 12 minutes and 30 seconds by mixing bromic acid, potassium dichromate (0.5M) and phosphoric acid in a ratio of 1: 1: 1, Experiments have shown that it is possible to have uneven parts.

Next, the mask pattern 230 of the stamp substrate is removed as shown in Fig. 3 (c). Various process techniques can be used to remove the mask pattern 230, specifically using an organic solvent such as acetone or an O 2 ashing technique.

3 (d), the metal catalyst thin film 220 is formed at the end of the protruding portion 212. Then, as shown in Fig. As described above, the metal catalyst thin film may be selected from gold, silver, platinum, iron, nickel, cobalt, copper, lead, and mixtures thereof, and it may suitably have a thickness of 20 to 50 nm. The metal catalyst thin film may be formed by dissolving a complex of a metal or an alkoxide of a metal in a solvent such as alcohol and then applying the solution on a stamp and drying the metal catalyst thin film or by a metal deposition method such as thermal deposition or sputtering. In the case of using the thermal deposition method, it was confirmed through experiments that the metal catalyst thin film was formed stably on the stamp substrate when the gold was deposited at a relatively slow rate of about 0.07 nm / s.

In this manner, a stamp including the base portion 210 including the concave and convex portions 211 including at least one protrusion 212 having the metal catalyst thin film 220 at the end portion thereof can be manufactured.

 4 is a view illustrating a method of manufacturing a stamp for manufacturing a nanostructure according to another embodiment of the present invention. Referring to Fig. 4, Figs. 4 (a) to 4 (c) correspond to Fig. 3 (a) to Fig. 3 (c). That is, in this embodiment, a mask pattern is formed on a stamp substrate in the same manner as described with reference to FIGS. 3A to 3C, and then the stamp substrate is etched with a stamp substrate etching solution to form a pattern having at least one protrusion The process of forming the concave-convex portion and the base portion including the concave-convex portion and removing the mask pattern of the stamp substrate is the same.

Then, in this embodiment, an adhesive layer is formed on the stamp substrate 200 as shown in Fig. 4 (d). It is to be noted that when the uneven portion 211 is formed on the stamp substrate 200, the adhesive layer 221 may be formed on the uneven portion 211 of the stamp substrate 200. The entire metal catalyst thin film 220 may be detached even if the material selected to form the metal catalyst thin film 220 is not deposited easily or is deposited on the stamp substrate 200. Therefore, the adhesive layer 221 is formed of a material which can be adhered to the stamp substrate before the metal catalyst thin film 220 is formed, and which can adhere the material forming the metal catalyst thin film. The material constituting the adhesive layer 221 may be specifically selected from titanium, chromium, nickel, and mixtures thereof. The thickness of the adhesive layer 221 may be about 3 nm, but may be about 3 nm to 7 nm for stability. In determining the thickness of the adhesive layer, it is possible to consider that the time and expense of the process is increased and the metal catalyst etching (MACE) reaction is hindered by the adhesive layer. In the case of using the thermal deposition method, it has been confirmed through experimentation that the adhesive layer is formed stably on the stamp substrate when titanium is deposited at a relatively slow rate of about 0.02 nm / s.

4 (e), the metal catalyst thin film 220 is formed at the end of the protruding portion 212. Fig. 4 (e) corresponds to Fig. 3 (d). In this embodiment, the same method as described with reference to Fig. 3 (d) can be used.

A stamp manufacturing method according to an embodiment of the present invention can manufacture a stamp including a base portion including a recessed portion having at least one protrusion having a metal catalyst thin film at an end thereof using a lithography method and a metal deposition technique, The nanostructure manufacturing method according to one embodiment of the present invention using the stamp and the wet chemical etching process can form a fine nanochannel as shown in FIG. 5 as compared with the conventional nanoimprint lithography technique. Particularly, a nanochannel having a V-shaped cross section can be relatively easily formed at a low cost.

In addition, the method of fabricating a nanostructure according to an embodiment of the present invention does not use an E-beam lithography or a stepper process, thereby making it possible to manufacture a nanochannel at a lower cost. In addition, unlike the FIB milling technique described above, since the process is not a sequential process, the time and cost are not increased even when the directness of the wafer is increased. Unlike the case of using the etching solution containing KOH, So that a circular nano structure as shown in Fig. 6 can be manufactured. These advantages are at the same time improved most of the problems of existing processes in nanostructure fabrication.

A method of fabricating a nanostructure according to an embodiment of the present invention is a method for fabricating a nano-fluidic channel for DNA analysis and a plasmonic lens capable of collecting SSPs (Surface Plasmon polarities) at one point without using FIB milling Making it possible to accelerate the industrial utilization of these products.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It goes without saying that various modifications can be made.

100: substrate
110: Nanochannel
200: stamp substrate 201: stamp
210: base portion 211: concave / convex portion 212:
220: metal catalyst thin film 221: adhesive layer
230: mask pattern
300: Near the edge of the metal catalyst thin film

Claims (21)

A method for manufacturing a nanostructure, comprising the steps of: a) contacting a substrate (100) with a stamp (201) for manufacturing a nano structure including a base (210) having at least one metal catalyst thin film (220) on one surface, Forming a sandwich-type bonded body in which a thin film is sandwiched; And
b) forming a nano channel 110 along the boundary of the edge of the metal catalyst film on the substrate by etching phenomena induced in the edge 300 of the metal catalyst film by immersing the combined body of the sandwich type in a substrate etching solution; ; ≪ / RTI >
The base 210 includes a protrusion 211 having at least one protrusion 212,
Wherein the metal catalyst thin film (220) is provided at an end of the protrusion (212). The method according to claim 1,
Wherein the planar view of the protrusion (212) is a pattern of the nanochannel to be formed. 3. The method of claim 2,
Wherein the depth of the concave and convex portion (211) is 15 占 퐉 to 30 占 퐉. The method of claim 1, wherein
Wherein an adhesive layer (221) is provided between the metal catalyst thin film (220) and the base part (210). 5. The method of claim 4,
Wherein the adhesive layer (221) is selected from titanium, chromium, nickel, and mixtures thereof. 5. The method of claim 4,
Wherein the adhesive layer (221) has a thickness of 3 nm to 7 nm. The method according to claim 1,
After step b)
c) separating the stamp (201) from the sandwich-type assembly and removing the metal catalyst remaining on the substrate. The method according to claim 1,
Wherein the metal catalyst thin film 220 is selected from gold, silver, platinum, iron, nickel, cobalt, copper, lead, aluminum, palladium and mixtures thereof. The method according to claim 1,
Wherein the metal catalyst thin film (220) has a thickness of 20 nm to 50 nm. The method according to claim 1,
Wherein the substrate 100 is a single crystal semiconductor substrate, a III-V compound semiconductor substrate, a silicon on insulator (SOI) substrate, a germanium substrate, or a silicon-germanium substrate. The method according to claim 1,
Wherein the base portion 210 is one of a single crystal semiconductor substrate, a III-V compound semiconductor substrate, a polymer substrate, a glass substrate, and a metal substrate. The method according to claim 1,
Wherein the substrate etch solution is a mixture comprising fluoric acid, sulfuric acid, hydrogen peroxide, silver nitrate, potassium chloride, potassium chloride, potassium chloride, potassium chloride, potassium chloride, platinic acid, ferric nitrate, nickel nitrate, magnesium nitrate, sodium persulfate, potassium permanganate, potassium bichromate Wherein the nanostructure is a solution. delete delete delete delete delete delete delete delete delete

Images